Summary

What does the map show?
The ‘nature network’ map shows those areas of Cornwall, currently excluded from statutory protection, that are considered the most valuable in terms of their existing biodiversity, habitats, connectivity and provision of key ecosystem services. Three prioritization classes can be viewed, which correspond to the most valued 5, 10 and 20% of currently non-protected land.

Prioritization methodology
Prioritization bands derive from a ranking of all areas outside of statutory protection. The methodology ranks areas based on their biodiversity value and their provision of ecosystem services, while also accounting for key constraining or facilitating factors that could affect the value of these benefits.
Rankings are assigned using Zonation methodology (REF), which has been widely used for land use and conservation planning. The methodology allows the relative weighting of different indicators of biodiversity value, ecosystem services and other factors while inherently accounting for the value of habitat connectivity. The approach is shaped around a methodology which allows easy updating/replacement of underlying data layers, adjustments to the perceived importance of different services, and can be applied to different spatial areas and scales.

Notes on the use and interpretation of maps
It is important to recognize some key aspects of the map and the underlying methodology by which it as generated:

• Rankings are assigned uniquely on the basis of current indicators of ecosystem services, biodiversity and factors like population or industrial activity that may affect the value of ecosystem services.
  
• High prioritization does not imply that the existing landcover or habitat features are those best able to deliver the greatest biodiversity or ecosystem service benefits. The biodiversity value and provision of ecosystem servics of even highly ranked areas may still often be improved.
  
• High prioritization generally favours areas that deliver multiple benefits.
  
• Cell rankings are not fully independent of each other. This dependence is most evident by considering the connectivity of cells. The value of a habitat ‘corridor’ is only meaningful if the two habitats that it links are maintained.

Valid potential applications include:

• Identification of additional areas for protection that build upon existing areas under statutory protection.
  
• Targetting of strategic resources to maintain biodiversity and the provision of ecosystem services.

Outline of Methodological steps

1. Define area for prioritization
Whole of Cornwall mainland at a resolution of 100m2.

2. Define irreplaceable habitats & existing protected areas:
These areas define the underlying network of habitats that are taken as ‘given’ and inform habitat area and connectivity benefits:

• Statutory designated areas: SSSI, SAC, SPA, national and local nature reserves.

3. Select biodiversity indicators
The relative importance of different habitats and other indicators of biodiversity are selected and weightings applied according to a judgement of their importance and the reliability of the data.

3a. Habitat types & features

• Landcover classes: a synthesis of several existing sources of landcover was used to define habitat types.
  
• Linear features: open watercourses and hedgerows.
  
• Habitat condition data: no suitable data for the whole of mainland Cornwall was available.
  
• Habitat Connectivity: is integral to the Zonation methodology.

3b. Species presence or distributions

• Species distribution data: not used due to concerns that the existing distribution data was not representative of distributions across the whole of mainland Cornwall.

3b. Non-statutory designations based on biodiversity value

• Country Wildlife Sites.

4. Ecosystem services
Each service is given a weighting to describe the relative importance ascribed to different ecosystem services and the reliability of the underlying data informing their calculation. The following key ecosystem services are estimated:

• Flood mitigation
  
• Carbon storage
  
• Pollination
  
• Water quality management for aquaculture, drinking water, beaches and for ‘not good’ catchments.
  
• Air quality management

Estimation of these services requires an assessment of the ‘demand for’ or ‘risk’ associated with each service (eg areas susceptible to flooding), as well as of service provision. Areas ‘at risk’ and areas of service provision are often spatially distant.

5. Facilitating factors
Factors that could facilitate the delivery and/or protection of existing assets and services are given a positive weighting reflecting their relative importance.

• Indicators of sympathetic land ownership or management such as National Trust land holdings or participation in higher-level environmental stewardship schemes.
  
• Unsuitability for alternative land uses such as steep slopes or north facing aspects.

6. Constraint factors Factors that could constrain the delivery and/or protection of existing assets and services are given a negative weighting according to their relative importance. A high negative weighting will ensure a low ranking is assigned to those areas to which the constraint factor applies.

• Suitability for alternative land use (opportunity costs):
  • Agricultural land grade.
    
  • Existing / recent planning commitments.
    
  • Mineral deposits.
    
• Presence of existing land features that reduce benefits/services:
  • Built-up areas
    
  • Recreational greenspaces (golf courses, playing fields…)
    
  • Roads / railways / infrastructure
    
  • Quarries

7. Additional layers for inclusion in visualisation but not analysis
Additional information layers are included to provide context for the analysis but do not affect prioritization. Such factors are given a zero weighting in the analysis. Such factors include administrative boundaries and the AONB.

Note: Integrating ecosystem services dependent upon accessibility
The provision of some ecosystem services depends on access / visitation to greenspace including a range of cultural/recreational/health benefits. Accessibility, however, can be detrimental to the value of other services including biodiversity, noise or soil loss mitigation.
Some simple options to reflect aspects of accessibility include:

• Weighting according to size of nearby resident population (which will favour protected areas close to population centres).
  
• Weighting by presence of access methods such as the density of foopaths or the right of open access to an area. This does not address wider aspects of accessibility like distance from poopulation centres, public or private transport options.
  
• Analysis of prioritizations for different administrative units - this will indirectly favour a wider spatial distribution of high priority areas.

Summary

What does the map show?
The ‘woodland opportunity’ map ranks areas according to the potential benefits of woodland creation. Three prioritization classes can be viewed, which correspond to the most beneficial 5, 10 and 20% of currentlypotential woodland sites.

Prioritization methodology
Prioritization bands derive from a ranking of all potential areas of woodland creation that are not excluded in advance (such as urban or existing woodland areas). The methodology ranks areas based on potential benefits in habitat connectivity and increased provision of ecosystem services, while also accounting for key constraining or facilitating factors that could affect the value, or likelihood of realising, these benefits.
Rankings are assigned using Zonation methodology (REF), which has been widely used for land use and conservation planning. The methodology allows the relative weighting of different factors while inherently accounting for the benefits of habitat connectivity. The approach is shaped around a methodology which allows easy updating/replacement of underlying data layers, adjustments to the perceived importance of different services, and can be applied to different spatial areas and scales.

Notes on the use and interpretation of maps
It is important to recognize some key aspects of the map and the underlying methodology by which it as generated:

• Rankings are assigned uniquely on the basis of potential benefits but does not capture all such benefits or indeed potential costs.
  
• High prioritization generally favours areas that deliver multiple benefits.
  
• Cell rankings are not fully independent of each other. This dependence is most evident by considering the connectivity of cells. The value of a habitat ‘corridor’ is only meaningful if the two habitats that it links are maintained.

Valid potential applications include:

• Identification of strategic areas for woodland creation.
  
• it is NOT suitable for assessing benefits of very small scale plantings.

Outline of Methodological steps

1. Identify all areas to exclude from woodland creation:
Identify areas not to be considered for woodland creation, such as urban areas, existing woodland or protected areas etc. Information on excluded areas will still inform the assessment of, for example, habitat connectivity benefits. All remaining areas are treated as potential woodland creation areas.

2. Identify ‘constraining’ factors:
Constraints are factors that are likely to reduce likelihood, or increase the cost, of realising woodland benefits, including current or high suitability for competing land use. Factors might include topographical constraints such as wind exposure, high grade agricultural land and percent building cover. Although not entirely excluded from consideration these factors are given a negative weighting in the analysis. A high negative weighting will ensure a low ranking is assigned to those areas to which the constraint factor applies.

3. Identify ‘facilitating’ factors:
Factors that will increase the likelihood, or lower the cost, of realising the benefits of wood creation opportunities. For example, steep slopes could be considered a facilitating factor as they can restrict alternative land uses, particularly agriculture. Each factor will be given a positive weighting in the analysis. Such factors are likley to include:

• Indicators of sympathetic land ownership or management such as National Trust land holdings or participation in higher-level environmental stewardship schemes.
  
• Unsuitability for alternative land uses such as steep slopes or north facing aspects.

4. Identify and estimate the relative value of woodland “benefits”:
Each benefit will be assigned a positive weighting. The calculation of benefits will generally involve an estimation of both the demand for, and the potential provision of the benefit from woodland creation although the methodologies for doing so vary between different types of benefit. These include habitat connectivity and area:perimeter benefits, as well as potential increases to ecosystem services from woodland creation.

5. Prioritization of “woodland creation opportunities”:
Analysis is undertaken through the Zonation methodology with the assigned ranking determining the prioritization band assigned to each ‘cell’. The Zonation methodology accounts for potential benefits to habitat connectivity. Zonation parameters will also determine the relative importance assigned to, for example, areas with a high single or rare benefit and those where woodland creation is likely to produce multiple benefits.